The objective of this prospective observational study of intracranial tumors in patients with neurofibromatosis type 2 (NF2) is to gain insight into the use of 18F-fluoro-deoxyglucose (FDG) and 3 -deoxy-3 -18F-fluorothymidine (FLT) positron emission tomography (PET)/computed tomography (CT) as a predictive measure of future tumor growth patterns.